Fans of Man Group have been rather conspicuous by their absence recently. The hedge fund giant has suffered a dramatic fall from grace, with the stock losing a third of its value in a month, meaning its share price is now three-quarters lower than in 2009.

The latest slide has left it vulnerable to relegation from the Footsie when the indices are next reshuffled in June, but yesterday Man was attempting a recovery as supporters finally started emerging from the woodwork.

Much of the firm's weakness has been pinned on the poor recent performance of its flagship AHL fund. However, Bank of America Merrill Lynch's Philip Middleton said that while the computer-driven fund "has been a bit dull this year", unless "AHL is 'broken', Man is evidently severely undervalued".

As a result, the analyst reiterated his "buy" rating, and he was not alone in his support – analysts from Credit Suisse were also doing their best to raise the morale of those investors still involved in Man. Saying that "over the medium term AHL performance will recover", they kept their "outperform" advice, although their 130p target price – down from 175p – was quite a lot lower than Merrill Lynch's of 230p.

Still, it was enough to see Man Group close the session high up the blue-chip index after advancing 2.3p to 95.7p. Traders were not too positive, however, saying it was little more than a dead-cat bounce, while noting that with Man trading ex-dividend next Wednesday, further falls would not be a surprise.

The FTSE 100 rose 27.6 points to 5,772.15, as – not for the first time this week – positive results from across the Atlantic provided support, with encouraging figures from the Wall Street giants McDonald's and General Electric.

There was no such positive read-across for Weir Group, however. The pump manufacturer was knocked back 52p to 1,700p by cautious outlook comments overnight from US rival Gardner Denver.

Another being hit by news from the States was Arm Holdings, with the Apple supplier's retreat of 22.5p to 585p leaving it in last place. The move was being pinned on the chip maker Qualcomm saying earlier in the week it was unable to meet demand. Arm was also pushed down by scribes from both Jefferies and Liberum telling punters to sell ahead of the group's first-quarter update on Tuesday.

Two years to the day since the Gulf of Mexico disaster, BP was pegged back 5.2p to 434.85p. JP Morgan's Fred Lucas – who has an "overweight" rating for the stock – took the opportunity to calculate that, if the tragedy hadn't taken place, the oil giant's market value would theoretically have been more than $90bn (£56bn) higher.

The gold medal position was snapped up by Severn Trent, with the water group gushing up 61p to 1,720p after the revival of bid speculation this week. However, JP Morgan picked Severn Trent's mid-tier peer Pennon as the "most attractive potential takeover candidate" among the UK utilities, prompting it up 15.5p to 751p.

There were no prizes for guessing the main shocker on the FTSE 250. With its "SuperDroop" nickname never being so accurate, fashion retailer SuperGroup plummeted a huge 217.7p, or 38.23 per cent, to 351.8p after being forced to issue a profits warning because it got its sums wrong.

Meanwhile, Cable & Wireless Worldwide slipped 2p to 32p in response to the announcement after the bell on Thursday that Vodafone (0.85p lower at 171.5p) has received a third extension to the deadline for it to decide whether to make a bid for the telecoms group.

Rockhopper – the only Falkland Islands explorer to make a commercial discovery – was pushed back 29.75p to 351.75p after the publication of a competent person's report on its Sea Lion field contained little further news on finding a partner for the project. Oriel Securities' Nick Copeman warned that the "shares are unlikely to perform until progress on a farm-out becomes clearer".

Meanwhile, Desire Petroleum, which holds a stake in part of the Sea Lion field, edged up 0.25p to 29.5p after announcing an update to its own competent person's report.

Fellow driller Bahamas Petroleum dropped 26.83 per cent to 7.5p following reports that the country's Prime Minister, Hubert Ingraham, has said that there will be no drilling for oil if his party is re-elected. The group – whose permits run out today – was also harmed by discouraging comments from a rival of Mr Ingraham.

On the fledgling index, SkyePharma's share price more than doubled, shooting up 44.12p to 85.5p, after European regulators recommended its asthma product Flutiform for approval. Adding to the good news was the drugs firm's announcement that it had been paid $10m because of the US launch of painkiller Exparel.